Vac to Waste
These vacuums remove water from the pond along with muck. We believe this is the only type of system for removing fine silt from a pond.
Water Pump MethodPumping muck out of a pond requires a fairly heavy duty pump. You need good flow, at least 1200 GPH. The pump also needs to handle debris.
Virtually all swimming pools have been using out of water (inline) pumps for years to vacuum. 3/4 to 2 HP costing $200-$500. Getting a used pump could work since cost to run isn't a concern. The nice thing about this system is the pump is in place. Just hook up the hose and start vacuuming. Could require a longer hose since the pump can't be moved.
Another option is to use a less expensive sump pump. About 1/6 to 1/2 HP and $60 to $90 in most hardware stores. The problem here is connecting a hose to the intake because there's no fitting.
DrawbacksLeaves, dead string algae and other large debris can be caught in the hose or pump causing a clog which can be hard to clear. Any fish or other creature pulled into the pump would be killed. A leaf canister can be used to catch leaves and large debris before getting to the pump. Also called Leaf Traps. Sold by swimming pool supplies for $50 - $100.
5-25% of water is lost. Removing large debris before vacuuming silt can reduce the water loss by reducing the amount of vacuuming needed. Also, waste water can be put into any large container like a 55 gal drum so the muck can settle to the bottom and the clear water on top pumped back into the pond. Takes about a day for most of the muck to settle.
Can be difficult to keep prime. No air can be allowed into the intake system or pump will stop working. Keeping all hose connections below water solves the problem.
Shop Vac$70 to $150 at most hardware stores. Also called wet/dry vacs. Very straight forward vacuum system. No prime needed, no prime to lose. Mainly for smaller ponds because of the reach.
DrawbacksIf vac falls into pond and floods motor it will likely short out and be destroyed. The short could also cause electrocution to anyone in the water and/or fish. Should only be plugged into a GFI outlet which is a safe guard, not complete protection. And vac should be positioned so it can't possibly fall into the water such below the wall of a raised pond or down hill from a pond or tie the vac to a tree. Just being careful isn't enough, everyone is careful. Setup so you don't have to be careful, so no matter what mistake is made the vac can't fall into the pond.
Reach can be limited to the wand length. Extensions can be purchased but most are friction connected and can come loose when vacuuming the more extensions are used. This can be fixed by duct taping the sections together.
Limited capacity. Short vacuuming before water must be removed from tank. Capacity can be greatly increased by hooking a larger container to the shop vac as with Floyd's Pond Vacuum.
Heavy when full of water. There are models with pumps inside to pump the water out like QPV. Normally these pump out model can't keep up with the in coming water so there may be periods of waiting before you can start vacuuming again. These delays in a small pond may be no problem.
Too much vacuum. For some people the amount of suction is just too much. Vacuum head sticks to liners, plants and fish get sucked up, etc... You can buy hoses with built-in Airflow Control to adjust your vac's power. Sources include TotalVac
SiphonBasically just a length of hose, normally 1" or less in diameter, where the end outside of the pond is below the waterline in the pond. The further below waterline the move vacuum. To start siphon put entire hose in pond and push underwater so all air is removed. Press your hand over one end to trap water and remove from pond releasing your hand when end is below the level of water inside the pond. That starts water flowing. Move the other hose end around the bottom of the pond to vacuum fine silt. Leaves, dead string algae is going to clog the hose so it's best to remove these before vacuuming silt.
There are products like the Shake-a-Vac, $25-$35 which help get a siphon going. But siphons are pretty easy to start with just a length of hose.
ManualTake a short length of PVC pipe, press your hand against one end to seal it and plunge the other end down to the pond bottom into the muck. Release your hand and the air inside the pipe will escape and water and muck will be drawn in. Place your hand back over the pipe to seal and remove the pipe. Remove your hand to dump the water and muck out of the pond. This type of device can be dolled up with a valve to replace your hand and/or a check valve on the bottom to keep water from going back into the pond. Either way this is a slow process for anything but small ponds.
There are many products using the manual type of vacuum including Grit-Gitter $30, Spa Wand $60 and others.